Method for the Absolute Measurement of Dynamic Properties of Linear Structures at Sonic Frequencies

Lyons, W. James; Prettyman, Irven B.

doi:10.1063/1.1698158

Cited by 19 publications

(9 citation statements)

References 11 publications

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“…The maximum forces occurred immediately after A, and the minimum after B. Since the duration of a complete cycle was approximatelỹ sec., forces and partial relaxations were completed in short intervals, the time element of which is comparable for variations in forces in a tire while operating at normal rates of speed [18]. While a tire may be subjected to intermittent dynamic forces during road use and continuous static forces when stationary, routine tests have been made only for dynamic fatiguing without interruption.…”

Section: Rh)mentioning

confidence: 99%

Effect of a Dynamic Fatigue Test on the Mechanical Properties of Tire Cords

Grant

Couturier

Rhodes

1951

Textile Research Journal

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Changes in the mechanical properties of cords subjected to dynamic fatigue were measured for cotton, mercerized cotton, and rayon tire cords. These data were obtained by the use of an instrument which subjected the cords under tension to localized dynamic forces under controlled atmospheric conditions. The forces, when observed on an oscilloscope screen, were found to vary during the flex cycle. Flex life and ultimate elongation were found to be cumulative, regardless of whether the cords were fatigued continuously or were allowed to relax with or without static tension between periods of flexing. Calculated activation energies for fatigue failure were less than those for heat degradation. From the differences in properties a qualitative evaluation of tire cord behavior could be made. THE FATIGUE-RESISTANCE of an automobile tire cord plays an important part in the performance of the tire. A tire in service must endure periodic and unequal stresses, relaxations, and compressions under varying conditions of moisture and temperature. The ability of the cord, the unit supporting structure of the tire wall, to withstand these varying forces depends upon its physical properties -its strength, elongation, and elastic behavior. While much has been reported in the literature about the effects of the forces on these properties, the interpretation of this type of information in terms of tire performance is still in the experimental stage.The previous interpretations have been made on the basis of data on the dynamic fatigue obtained on testing machines of radically different designs [1,2,7,12,14,19,20,25,27] . But since none of the available machines was considered sufficiently reliable to be accepted as the standard by the American Society for Testing Materials, a special instrument was constructed for the present work which bends cords while subjecting them to localized dynamicfatigue factors. This machine provided a means of comparing the changes undergone in strength, elongation, and energy characteristics by cotton, mercerized cotton, and rayon tire cords after fatiguing under different conditions. The results, after the necessary limitations of the test are taken into account, indicate a characteristic pattern of performance for each of the materials examined.The Instrument

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Section: Rh)mentioning

confidence: 99%

Effect of a Dynamic Fatigue Test on the Mechanical Properties of Tire Cords

Grant

Couturier

Rhodes

1951

Textile Research Journal

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“…The precision with which E can be calculated does not warrant retaining the relatively much smaller addend id• 2, and accordingly, energy loss at unit stress-amplitude has been calculated [42] aspOo7'/E2. This quantity, like that referred to unit strain-amplitude, is not a perfect constant, blit varies when strain-amplitudes cover a wide range.…”

Section: Measurement Of Ljynamic Propertiesmentioning

confidence: 99%

“…To this end, a quantity that does not depend on the strain amplitde Sm//1 o, and that is hence more nearly a material constant than H was introduced [42]. This quantity C,v has beer called, preferably, the energy loss at unit stra.n-amnli --tude.…”

Section: Measurement Of Ljynamic Propertiesmentioning

confidence: 99%

“…* A schematic diagram of typical apparatus is shown in Fig. 5.2 and operation of such a stretch vibrometer have' been described by Lyons [42] as follows: ".…”

Section: Measurement Of Ljynamic Propertiesmentioning

confidence: 99%

“…Methods thus far developed for the measurement of the dynamic propr+riaQ of textiles have generally involved the use of a vibrating mass to which the specimen is attached [41,42,92]. * A schematic diagram of typical apparatus is shown in Fig.…”

Section: Measurement Of Ljynamic Propertiesmentioning

confidence: 99%

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Impact Phenomena in Textiles

Lyons¹

1962

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Interaction of Polymers and Mechanical Waves

Baker¹,

Heiss²

1952

Bell System Technical Journal

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New techniques of Mason, McSkimin, Hopkins and co‐workers for generation of shear waves over the frequency range 2 × 102 to 2.4 × 107 cps have been used to study mechanical properties of chain polymers. Polymer solids, melts and dilute solutions, representing the main states in which plastics and rubbers are fabricated or used, were explored to find the characteristic relaxation times, rigidities and viscosities of various chemical structures. Polyisobutylene, hevea rubber, polydimethyl siloxane, vinyl chloride‐acetate copolymers and plasticized nitrocellulose were compared with polyethylene and polyamides as examples of the range of solid properties encountered. As melts, several polyisobutylenes, polybutadiene, polypropylene, polypropylene sebacate and poly‐α‐methyl styrene were investigated as models for varying degrees of chain substitution. Chain rigidity in, for instance, polyisobutylene, seemed to reflect visco‐elastic over‐all configurational changes up through the kilocycle range, but nearest neighbor interactions took over in the megacycle region, leading to moduli of 109 dynes/cm2 even for syrupy fluids. In dilute solution, polyisobutylene, polystyrene, natural rubber and polybutadiene microgel exhibited characteristic dynamic viscosities and rigidities depending linearly on concentration. Presumably, this reflects mechanical properties of isolated chains. Some possible models were suggested for the frequency dependence of such properties.

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Method for the Absolute Measurement of Dynamic Properties of Linear Structures at Sonic Frequencies

Cited by 19 publications

References 11 publications

Effect of a Dynamic Fatigue Test on the Mechanical Properties of Tire Cords

Effect of a Dynamic Fatigue Test on the Mechanical Properties of Tire Cords

Impact Phenomena in Textiles

Interaction of Polymers and Mechanical Waves

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